In leading industries (aeronautic, space and automotive sectors or other manufacturing industries), the required and necessary precision during the shaping of parts may be high and the techniques put in place to meet these requirements are becoming increasingly complex.
When a metal part is to be shaped, stamping is very often the chosen method, since this method is reliable and can be controlled very readily. Stamping consists in a plastic deformation of a plate of material, under the action of a pressure, so as to give the plate the shape of a predetermined mold. Even though the technique is generally used on metal materials (steel, aluminum, etc.), it can also be applied to numerous plastics materials such as PVC, polyethylene, polycarbonate, etc.
One of the variants for carrying out forming by stamping is the process known as elastoforming (Guerin process), the principle of which is to apply a stress to an elastomer (for example by means of a ram) which then performs the function of a punch or die. The elastomer transmits the pressure to which it is subjected to the plate to be deformed, the latter hugging the shape thereof during the stamping operation.
Patent application EP 0 376 808 (Isoform, 1988), which relates to a method and device for stamping sheet material with a punch which is deformable under the action of a plunger, is known in particular in this field.
However, one disadvantage of this method lies in the fact that it is only possible to carry out shallow stamping operations in lightweight metals of small thicknesses (for example: aluminum). In practice, the method is limited to a sheet metal thickness of 1.5 mm.
Another disadvantage of this shaping method is that of the elastic return which occurs after relaxation of the part to be formed. This effect is greater or lesser depending on the material in question and may prove to be problematic when it is no longer negligible when considering the expected precision.
U.S. Pat. No. 7,954,357, which discloses a method and device for stamping flat sheet material with a deformable punch of substantially flat shape, is also known.